The present invention is directed to an opto-electronic arrangement for a line-by-line scanning of color originals in reproduction technology. The arrangement includes a light source, a shaped transducer whose output is constructed to provide a linear optical pattern or light band which corresponds to the line to be scanned, a filter means and a line of photodiodes. The filter means will contain filters which are set for color separation of the light of the light source into individual colors, for example, red, green or blue.
Luminophore tubes are presently often employed in reproduction technology as linear light sources for scanning originals. In addition, a surface illumination is employed in scanning originals in combination with the movement of a CCD line in a feed direction.
These illumination arrangements have the disadvantage that the optical efficiency is low and that they are not suited for illuminating the original line-by-line with chromatic light.
U.S. Pat. No. 4,490,740, whose disclosure is incorporated by reference thereto, discloses an arrangement for multi-color scanning of originals comprising a stationary original stage, a light pick-up and an illumination unit including a rotating filter wheel for generating the multi-color scan light. The light passes through the filter wheel and is converted into a line-shaped optical pattern or light band by means of a fiber-optical shape transducer of the illumination unit. This band shape pattern is then conducted across the original. The light reflected from the original will proceed via a deflecting mirror in an optical arrangement onto a line of photodiodes. Both the illumination unit of the filter wheel and the shape transducer, as well as the light pick-up which comprises the deflecting mirror, optics and a line of photodiodes are moved under the stage supporting the original and are moved along the original for scanning the original. This has the disadvantage that the fiber-optical shape transducer is moved and, thus, bent so that it disadvantageously changes its optical transmission properties and that all non-uniformities in the overall motion sequence, as well as jolts, produce image disturbances.
The arrangement of this patent also has the further disadvantage that it has poor light efficiency and that, in addition, the intensity distribution of the light at the output of the optical pattern or light band formed by the fibers is nonuniform. The poor efficiency results occur because the light at the output of the individual fiber optics will diverge. The different intensity distribution is caused by the different properties of the individual fibers and leads to streaking in the reproduction. The intensity distribution additionally changes due to the motion of the fiber-optical transducer so that a further deterioration of the image quality will occur.